From: Reindl Harald
Date: June 13 2013 11:19am
Subject: Re: open files in mysqld 5.1.53
List-Archive: http://lists.mysql.com/mysql/229521
Message-Id: <51B9AAB2.1090204@thelounge.net>
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Am 13.06.2013 12:07, schrieb Hartmut Holzgraefe:
> this combined with file-per-table engines like MyISAM or ARCHIVE (maybe=
with InnoDB with innodb-file-per-table
> being active, too?) may well lead
> to a lot of file handles being used, and this again combined with the t=
able_cache keeping opened tables (and the
> related files) open for later
> reuse can lead to a lot of file handles being used and kept in use ...
> FLUSH TABLES may help here by at least releasing those handles that are=
> just kept open by the table cache ...
it is a simple calculation but the handling is wrong
4861x32 =3D 155552
471206 / 155552 =3D 3
each table has 3 files on disk (frm, myd, myi)
however - i do not buy the logic that every of the
32 cached threads had accessed ANY of the 4861
tables - impossible, there are databases from
websites which have very low traffic and so
it is unlikely that in 3 days avery thread has
accessed every table on the machine
______________________________
[root@localhost:~]$ lsof | grep mysqld | wc -l
471206
nobody but oracle knows why there are so much file handles
and this is MySQL 5.5.32
[--] Data in MyISAM tables: 481M (Tables: 4861)
[OK] Highest usage of available connections: 6% (32/500)
[OK] Thread cache hit rate: 99% (32 created / 425K connections)
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